Quality statement 2: CA125 blood test – age-specific thresholds
Quality statement
Adults aged 40 and over with persistent symptoms that suggest ovarian cancer have an urgent, direct access ultrasound scan of the abdomen and pelvis if indicated by their age and serum CA125 level. [2025, updated 2026].
Rationale
Ovarian cancer is associated with late diagnosis, with around 60% of people diagnosed at stage 3 or 4, and 30% diagnosed following an emergency presentation (see NHS England's interactive dashboard data on incidence by stage for 2023 and NHS England's routes to diagnosis interactive dashboard for 2020). Early symptoms of ovarian cancer can resemble other pelvic or abdominal conditions, making early detection challenging. Serum CA125 levels inform primary care decisions about when to arrange a direct access ultrasound scan for adults aged 40 and over who have persistent symptoms of ovarian cancer, based on their age and CA125 level.
Quality measures
The following measure can be used to assess the quality of care or service provision specified in the statement. It is an example of how the statement can be measured, and can be adapted and used flexibly.
Process
The proportion of adults aged 40 and over with persistent symptoms that suggest ovarian cancer who have an urgent, direct access ultrasound scan of the abdomen and pelvis based on their age and serum CA125 level.
Numerator – the number in the denominator who have an urgent, direct access ultrasound scan of the abdomen and pelvis.
Denominator – the proportion of adults aged 40 and over with persistent symptoms that suggest ovarian cancer and a CA125 level that indicates an urgent, direct access ultrasound scan.
Data source: Data can be collected from information recorded locally by healthcare professionals and provider organisations, for example, from patient records.
What the quality statement means for different audiences
Service providers (such as GP practices) ensure that healthcare professionals can recognise the symptoms of ovarian cancer. They agree service specifications for testing serum CA125 and carrying out urgent, direct access ultrasound of the abdomen and pelvis if indicated by age and serum CA125 level.
Healthcare professionals (such as GPs) recognise the symptoms of ovarian cancer and arrange serum CA125 testing. They arrange an urgent, direct access ultrasound of the abdomen and pelvis if indicated by age and serum CA125 level.
Commissioners commission local blood testing services that perform serum CA125 blood testing for adults with persistent symptoms that suggest ovarian cancer. They commission local services for adults to have an urgent, direct access ultrasound of the abdomen and pelvis if indicated by their age and serum CA125 level.
Adults aged 40 and over with persistent symptoms that suggest ovarian cancer have a serum CA125 blood test and, depending on their age and the test result, an ultrasound scan arranged by their GP and carried out within 2 weeks.
Source guidance
Suspected cancer: recognition and referral. NICE guideline NG12 (2015, updated 2026), recommendations 1.5.8 and 1.5.9
Definitions of terms used in this quality statement
Persistent symptoms that suggest ovarian cancer
Symptoms include, particularly in those aged 50 and over:
-
abdominal distension (often referred to as 'bloating')
-
feeling full (known as satiety) and/or loss of appetite
-
pelvic or abdominal pain
-
increased urinary urgency and/or frequency
-
unexplained weight loss
-
unexplained fatigue
-
unexplained changes in bowel habit, or
-
symptoms that suggest irritable bowel syndrome if aged 50 or over.
[NICE's guideline on suspected cancer: recognition and referral for suspected cancer, recommendations 1.5.2, 1.5.3 and 1.5.5]
If indicated by their age and serum CA125 level
Ultrasound of the abdomen and pelvis depending on age and serum CA125 according to the thresholds below:
| Age group (years) | CA125 threshold (IU/ml) |
|---|---|
|
40 to 49 |
35 IU/ml or greater |
|
50 to 59 |
31 IU/ml or greater |
|
60 to 69 |
24 IU/ml or greater |
|
70 to 79 |
25 IU/ml or greater |
|
80+ |
31 IU/ml or greater |
[NICE's guideline on suspected cancer: recognition and referral, recommendation 1.5.9 and table 1]
Urgent, direct access ultrasound
An ultrasound to be done within 2 weeks, with primary care retaining clinical responsibility throughout, including acting on the result. [NICE's guideline on suspected cancer: recognition and referral, terms used in this guideline]